What Do Dimensions 5-14 in String Theory Really Mean?

[Aftermarth]

I was told by my old physics teacher that there is proof (mathematically) for around 14 dimensions or something crazy like that. I think he said it was in relation to string theory and the amount of dimensions they need to oscillate as we think

but seriously, we have x,y,z planes and time

what more could we need?
so what does dimensions 5-14 cover?

 

[Shackleford]

Eleven dimensions is needed in string theory.

 

[AzonicZeniths]

so what does dimensions 5-14 cover?

It covers more spatial dimensions. I'm 90% sure that no matter how many spatial dimensions there are, there is only one time dimension.

 

[Flexo]

It covers more spatial dimensions. I'm 90% sure that no matter how many spatial dimensions there are, there is only one time dimension.

I don't think one time dimension is absolutely necessary for a hypothesis to be sound.
The extra dimensions(5-10 spacial) are only needed for strings to be able to move in different fashions.
Consider a one-dimensional universe. There exist two strings on that plane, both charged electrically positive. Some force pushes them together(the means by which they come together is not important). As they come together, more and more repulsion occurs, and the points want more and more to separate in some way. The force that is pushing them together, however, is too strong to fight, and so the string bend into another dimension.

Or, for an example that's commonly used for plate tectonics, pretend I have two folded towels on a table. I push them together, and eventually they bend up due to the forces acting on them.

Without the extra dimension that they bend into, the theory breaks down. Keep in mind this is not a great metaphor.

 

[AzonicZeniths]

That is a great metaphor. But, theoretically what you just stated, means that we could force two things together and they would move into a fourth spatial dimension?

 

[Flexo]

That is a great metaphor. But, theoretically what you just stated, means that we could force two things together and they would move into a fourth spatial dimension?

Very theoretically. However, for our purposes, three dimensions is enough. Only at a very small scale do things start to need more room to act.

 

[jablonsky27]

check out the kaluza-klein theory. it too talks of more than 4 dimensions(3 spatial ad 1 of time). according to it, the extra dimensions have curled up on themselves to such a degree to be hardly noticable. something like taking a rectangular piece of paper(2 dimensions) and rolling it up a lot so that it becomes a tube with a very small radius. so it has effectively become a line(1 dimension).

 

[gstrosx]

if there were more than 3 dimensions then why can i not move in more than 3 directions (neglecting the 0.5d of time)

 

[Phrak]

The count actually runs something like this. String theories requires 10 dimensions. Super Symmetry requires 11 dimensions. The two theories come together in some fashion in an 11 dimensional points theory, or M theory, or brane theory.

At one time it was said that string theory required either 10 or 24 dimensions. As near as I can understand, the extra 14 dimensions are still around but thought of as internal degress of freedom.

These extra dimensions--over 4, implement the 4 forces.

 

[Aftermarth]

so if these other dimensions represent forces, does that mean we exist in more than 4 (or 3.5) dimensions as well?

it is really hard to visualize as we are so use to our 4
reminds me of trying to visualize the 'singularity' hahah

there is some experiment too where you take a strip of paper, and you turn one end upside down, then bring it back to meet the other end so that you have a 1d shape (only one surface). is that like the paper tube one posted before?

 

[Phrak]

Aftermath. It's difficult to visualize this of course, but, yeah we're already there, and as jablonski says adding one rolls up like a tube of very small circumference.
Where does this 3.5 dimension stuff come from? surely not from established physics or any significant thought.

 

[Monocles]

I've never seen anyone say it before but I'm guessing some people might consider time to be only half a dimension because we only move in one direction through it.

 

[Diffy]

I've never seen anyone say it before but I'm guessing some people might consider time to be only half a dimension because we only move in one direction through it.

So far as you know...

 

[Nabeshin]

There has been talk (not sure how much research or study into) of more than one time dimension. I think it simply stems from asking why there shouldn't be another time dimension, and considering the ramifications of another one. After all, I would argue we hardly understand time at all, so the possibility certainly isn't off limits.

 

[AzonicZeniths]

I think I know what you are saying about having more than one time dimension, there is a theory that states that all electrons in existence are exactly the same because they are all copies of each other. Some are just going backwards in time, and some are going forwards, but when this forward-backward time movement happens, things can make carbon copies of themselves. I read this in the book, Beyond Einstein- The cosmic quest for the theory of the universe. by Michio Kaku. http://www.amazon.com/dp/0385477813/?tag=pfamazon01-20
This theory would suggest the two, forward and backward time dimensions.

 

[Nabeshin]

I'm not really sure how serious to take Kaku anymore. Seems he just writes a lot of pop-sci books and does NOVA specials these days. :(

 

[AzonicZeniths]

I'm not really sure how serious to take Kaku anymore. Seems he just writes a lot of pop-sci books and does NOVA specials these days. :(

Yes, he does, but he is still a reputable physicist and a very good one at that, a person who writes pop-sci books can still be very reputable. And, his books do go considerably in depth.

 

[TR345]

Is the rolled piece of paper analogy an example of only one extra dimension?

Electrons can be at multiple places at one time. Is this one of the reasons why we need more dimensions?

Are these extra dimensions simply answers to unexplained movement, ie. when something behaves contradictory to how is is expected. Like if physical laws say it will do one thing in 4 space, but it does not, so it must be operating under physical law, but just in more dimensions than previously thought?

 

[robertm]

Yes, he does, but he is still a reputable physicist and a very good one at that, a person who writes pop-sci books can still be very reputable. And, his books do go considerably in depth.

Agreed. There is nothing wrong with attempting to spread a few shreds of truth to the masses. Neil Degrass Tyson is a good example.

Also Kaku started with physics and ended up on t.v... not the other way around.

 

[jablonsky27]

no, the rolled paper analogy is for many dimensions. atleast this is how i read it in a book loong back(i ll dig it up).

as far as i know, all these theories sprang up because of inconsistencies in quantum physics at the time. 'infinities springing up all the time' is a well advertised problem. another motivation was in trying to unify GR with quantum physics.

and as mentioned earlier, the extra dimensions are not of space.

 

[Loren Booda]

Kaku, like any effective communicator, is a good salesman too. I saw him at the Smithsonian where he was "hawking" his book on Einstein.

 

[TR345]

Kaku kind of bores me, at least when he is on TV. I'm not gullible enough to buy his quasi sci-fi stuff. I have never read any of his serious stuff though, I'm sure he knows more than me, so I can't dis him, he obviously is successful, and I would guess that is what he is going for, so good for him. He loses my interest though because he talks mostly about stuff that I believe to be too far fetched.

 

[Aftermarth]

what books does this Kaku write... if i ever get some spare time i might have to read this if you guys seem to think it is worth it?
maybe in mid-semester break or something lol

so a forwards and backwards time dimension? that sounds crazy. if a backwards time existed would it be possible for us to move into it?

 

[AzonicZeniths]

Kaku mostly writes stuff about theoretical astrophysics, stuff I really enjoy. And yes, you should really read a Kaku book, he is a very talented author and a very in depth physicist.

And, I am not sure if it would be possible for us to move into the backward time dimension, the only way we could is if we turned all the electrons in our body into antimatter electrons. (I think :\)

 

[madmike159]

Is the rolled piece of paper analogy an example of only one extra dimension?

I like to think of extra dimensions as a human hair, from far away it looks 1D but when you look close up you can see its extra dimensions. It is the same for higher diemesions but on a smaller scale. It could also be that we are inside a much larger dimesion and seem very small in comparison, but i think this sounds a bit si-fi.

 

[Twigstar]

I'm still not seeing what these other dimensions are, based on this conversation. I haven't taken the effort to enlighten myself thus far, but it appears not many people have either. So what you're saying here, is that in order to class a dimension as such, you just need to exert a force in a way that is still relative to our known, three dimensional, view? To me, dimensions has always meant that of visual perception, or otherwise, an interactive state. It's not sounding like such?

So, in short, what are these dimensions? (Metaphors not required).

 

[madmike159]

Its very hard to explain what extra dimensions are like, there out side of what we know so it is hard to imagine and even harder to explain. There really used to make the maths of string theory and super symmetry.

 

[TR345]

What I would like to understand is the differences between these extra dimensions. They add
7-10 extra dimensions, but what is the difference between dimension 5 and dimension 6 etc. Why the need for so many when we have such a hard time understanding just one extra? Does anyone know how the extra dimensions are represented mathematically and how they differ in that sense?

 

[pallidin]

I'll take a stab at this.
The progression of dimensions are not necesarily direct or related. For example, dimensions 1-3 are spatial, and even at that, whereas dimensions 2 and 3 are easily understood and conceptualized, dimension 1 does not exhibit the the same aspect, so proof of "spaciality" could be argued, and Dimension 2 is not "tangeable" in the sense that who has ever constructed a true 2-D object(or 1-D).
Dimension 4 could be described as a relationship of change.
Given this, Dimensions 3 and 4 are our conceptualized reality with abundant proof of their reality in our world, so-to-speak.
To complicate matters further, D-4 is non-linear. It can go forward, backwards or into an infinie loop.
D-5, in a similar sense is removed from the constraints of D-1 through 4, but how could one describe it? I don't know.

 

[Aftermarth]

so d-5 can go forwards, backwards, into an infinite loop and still do other things?
or could it be like a combination of the four previous ones like a time-position reference?

and how on Earth do u prove that an extra dimension exists using maths? or is it mere speculation?

 

[pallidin]

Well, I quess that my point in all of this, Dimensions are weird. And I do not possesses knowledge of them other than my own thoughts.
Are higher dimensions a combination of the lower ones? Perhaps, but there's a problem with that. Try, for example, to degress the d-4 into d-1, d-2 and d-3 components. Seems rediculous doesn't it? How can pure time be degressed into components of physicality!
Another way to look at that problem is when we use d-2 to represent d-3, such as a line drawing on paper of a cube. Visually it can be very convincing, but it is an illusion without the form or substance of a true d-3 cube!

Now it gets really strange and even contentious... does d-1 really exist?
Think about a point without length or volume, which would be d-1.
How could that even be possible?
My contention is that when a "point" exists it must have volume because it occupies some region of space, however incredibly small.
Similarly, d-2 is non-sensical because it presuposes a d-1 with length and, again, no volume.
How could that be possible! A line, however thin, must occupy space.

So my contention is that everything is d-3 and beyond. The idea that an electron is a "point particle", for example, makes no sense to me with respect to it being d-1.

In other words, d-1 through 3 are considered vector qualities, however, the vectors of d-1 and d-2 have never been truly shown to exist apart from d-3, except mathematically.

So therein lies the problem, and even more so with d-4. How "time" became an acceptable definition of d-4 is beyond me, as I believe it is a trans-dimensional quality simply referencing an aspect of "change"
I do not view time as a dimension at all, rather that it references changes in all dimensions.

My brain is fried, I'll leave this alone for now...

 

[Aftermarth]

haha its a really hard topic hey..

i (on the adivce of other people in this thread) have picked up a copy of Kaku's Hyperspace book, along with his Quantum Field theory.
One thing i can't help but forget is one of the original proofs for a fourth spatial dimension being a modification of pythagoras. In 2D, a^2 + b^2 = c^2 in a triangle.
in 3D (a cube) a^2 + b^2 + c^2 = d^2 where d is the diagonal of the cube.
so 'logically' it can be assumed a^2 + b^2 + c^2 + d^2 = e^2 in what would be a 4D cube.

ok, I am not worried about the numbers here, that would seem to all add up properly, but the issue lies in what a 4D cube would be? I mean, what is the exact definition of a cube in the first place? And couldn't this go on forever, sure, i know its not the only definition of another dimension, but imagine what it could mean.

And reading this sure is helping i must say. But does anyone have some reasoning for why a fourth spatial dimension helps create a grand-unified theory? Kaku mentions waves in the 4th spatial dimension solves lights medium to propogate through, and that it can bond gravity to electromagnetism. And, (not finished yet) that the more dimensions you add, the easier the laws of nature become?
How so!? doesn't nature exist in the 3D we do - or does the math we create exist into more dimensions?

 

[TR345]

I think that dimensions 1-3 depend on each other in that they don't seem to be represented alone, but together they represent the degrees of possible movement. They are spatial dimensions, and the universe is 3d. Time is a little different. Without time the universe is just 3d, but time is actually bonded to the spatial dimensions according to relativity. In relativity, time is dependent on acceleration and gravitation. The more gravitation and or acceleration, the slower the clock will tick relative to a clock ticking under lesser gravitational and or acellerational magnitudes. I guess time is a factor of the interaction of
mass-mass-space which includes 3 space, so the 4 dimensions according to relativity are explicitly bonded and dependent on each other.

If you wanted to get crazy could you not call gravity a dimension, and call momentum a dimension? Could you call electrical charge or lack of a dimension? I guess they are excluded from being classified as dimensions because they are considered forces?(except gravity) I suppose that it may be thought that gravity is a side effect of the 4 dimensions and 4 forces, but attempts to link them have failed right?.

 

[Aftermarth]

well i wouldn't call gravity or momentum a dimension because they do act in the four that we already have. Kaku again seems to think that all of these forces can be combined into a grand theory of everything in five or six dimensions.. now that would be cool

how far could humanity go if we learned how all the forces interact? Could we then manipulate the world around us to be what we want?

i do like the example of the people who live in a 2D world being peeled off it and taken into our 3D world. They would only see everything still in 2D, but things would be appearing and disappearing as it moves past in the 3rd dimension because they can't see depth. So if we were peeled out of our world and taken to the 5th dimension, the effect would be the same. it would be very weird with lots of things we don't understand moving in ways we can't comprehend, but other than that we would see things almost normally... makes you think doesn't it?

 

[TR345]

The only thing is that if these extra dimensions do exist, they are supposed to only apply to very small things that are invisible to us right? The strange things that we see are observations such as gravity inertia etc. So maybe a photon or a quark or something lives in this extra dimensional world. The same way that we don't observe things the way they would, they wouldn't observe things the way we would(if they had eyes that is). Maybe the unexplained things we see are actually the forces and laws of physics which to us are no different than they way a 2d person would view a 3d world? To a photon, from their view if they had one, maybe the forces and gravity are plain as day in how they work?

 

[Aftermarth]

if only we could find all this out. it would be so great to know. i spose this whole thread is built on the desire to know what actually is a fifth dimension and the ones after it.

curious thought:
if a 2d representation of a cube is two squares joined together by lines
then a 3D representation of a hypercube (a 5D variation of our 3D cube) would look like two cubes joined together by lines...
so now try imagining what the actual thing looks like... *brain explodes*

http://www.geocities.com/liviozuc/hyperimages/acolori.gif

wow...

a hypothesis is that gravity is merely waves in the 4th spatial dimension which we can't see... how plausible would that be?

 

[Alex48674]

4d Cube
http://youtube.com/watch?v=Y9KT4M7kiSw

String Theory
http://youtube.com/watch?v=YtdE662eY_M
http://youtube.com/watch?v=L3CnoNdLSao

So who else is writing some nice reputable books on the subject? I was going to order a book by Brian Greene and maybe Kaku.

 

[Aftermarth]

um I am not sure who else writes good books on this... i didnt even know about Kaku until this thread...

ne one with any ideas?

ps... Kaku's Hyperspace is definitely worth a read

 

[aguycalledwil]

Originally, scientists noted that the mathematics of string theory faile when you pass ten dimensions, leaving them to believe that there must be ten dimensions. However, after a while, they realized something (I can't quite remember what) which indicates an eleventh dimension.

 

[Aftermarth]

can we get a bit more detail on that?

i loved reading about how putting einstein's and maxwell's equations together only took the addition of the fifth dimension :)

so one of our greatest discoveries is 15 = 10+4+1 :D

 

[aguycalledwil]

I quote from a book I read by Michio Kaku, "In 1994 another bombshell was droped. Edward Wittan of Princeton's institute for advanced study and Paul Townsend of Cambridge University speculated that all five string theories were in fact the same theory - but only if we add an eleventh dimension. From the vantage point of the eleventh dimension, all five theories collapsed into one! The theory was unique after all, but only if we ascended to the mountaintop of the eleventh dimension.
In the eleventh dimension a new mathematical object can exist, called the membrane (e.g., like the surface of a sphere). Here was the amazing observation: if one dropped from the eleven dimensions down to ten dimensions, all five string theories would emerge, starting from a single membrane. Hence all five string theories were just different ways of moving a membrane down from eleven to ten dimensions."

 

[Dfnoboy]

http: //revver. com/video /99898/i magining -the-tenth-dimension/


I had to make spaces in the URL because I need 15 posts to register...
but I thought I'd share this.

 

[Minkus]

It's all very simple...

...but unfortunately untrue
revver . com/video/99898/imagining-the-tenth-dimension/[/url]

 

[Minkus]

snap!

 

[Aftermarth]

so adding all these dimensions makes the maths becoming increasingly elegant and beautiful. and it sounds all good and fine. just one thing which i was thinking of today bugs me - we add all these dimensions but has anyone actually thought what they mean - like say the 10 dimensions for the 5 string theories.
adding the eleventh collapsed them into one -
but what is the difference from 11 to 10?

 

[aguycalledwil]

I guess that after ten dimensions, the mathematical side of it collapses. Ten is the largest number at which the "maths of the dimensions" will work at.

 

[david s j]

I believe there are only the dimensions we have now in this universe. to say we have more dimensions and more parallel worlds is a little bit foolish and fancy full to say the leased.
The cat in the box experiment when its both alive and dead at the same time
was derived to propell this theory of multipulll worlds.
which ever way you look at it , after the cat has been put in a box with radio active
substance and poisen broken by a hammer triggered radioactive substance
the cat is dead
have you seen monty python scetch my dead parrot
The perpetual thinking in this field of multiple worlds is a compleat waste of time
and would be better spent producing a self producing H2 vehical avoiding
H2 storage and disdrabution problems

atoms can be in two places at once, its only time that tells us where they are
in the one universe.
and its time that puts them in two places not two or more universes.

David Stuart Jones 23/9/51

 

[Shackleford]

I believe there are only the dimensions we have now in this universe. to say we have more dimensions and more parallel worlds is a little bit foolish and fancy full to say the leased.
The cat in the box experiment when its both alive and dead at the same time
was derived to propell this theory of multipulll worlds.
which ever way you look at it , after the cat has been put in a box with radio active
substance and poisen broken by a hammer triggered radioactive substance
the cat is dead
have you seen monty python scetch my dead parrot
The perpetual thinking in this field of multiple worlds is a compleat waste of time
and would be better spent producing a self producing H2 vehical avoiding
H2 storage and disdrabution problems

atoms can be in two places at once, its only time that tells us where they are
in the one universe.
and its time that puts them in two places not two or more universes.

David Stuart Jones 23/9/51

Ditto. There's only one universe.

 

[madmike159]

I believe there are only the dimensions we have now in this universe. to say we have more dimensions and more parallel worlds is a little bit foolish and fancy full to say the leased.
The cat in the box experiment when its both alive and dead at the same time
was derived to propell this theory of multipulll worlds.
which ever way you look at it , after the cat has been put in a box with radio active
substance and poisen broken by a hammer triggered radioactive substance
the cat is dead
have you seen monty python scetch my dead parrot
The perpetual thinking in this field of multiple worlds is a compleat waste of time
and would be better spent producing a self producing H2 vehical avoiding
H2 storage and disdrabution problems

atoms can be in two places at once, its only time that tells us where they are
in the one universe.
and its time that puts them in two places not two or more universes.

David Stuart Jones 23/9/51

The cat experimant is to disprove Bohr's idea of particles existing in every stat until someone looks at them. If Bohr's theory was true the cat would be both dead and alive in the same place at the same time. Which is stupid, there can be other dimensions not sure about other universes.

 

[Alex48674]

Why do you say it is foolish and fanciful to think there might be more then 3 spatial and 1 time dimensions? Many leading physicists think there are more and with good reason.